Shape memory polymers (SMPs) are polymers that regain their original shape when heated above their glass transition temperature (Tg). Articles are formed from shape memory polymers by first heating above the glass transition temperature and shaping the polymer, then subsequently fixing the shape by cooling to below the glass transition temperature. During deployment, the shaped article is heated above the glass transition temperature or slightly below the glass transition temperature to allow recovery of the first molded shape.
Shape memory polymers are useful as materials of construction of elements for a variety of downhole applications, particularly those that require the sealing off of a portion of a borehole or constricting the spacing around an element, whether coaxial with the borehole or otherwise. Shape memory polymers can also be used in sand control applications.
In addition to temperature change, the shape memory effect can also be triggered by an electric or magnetic field, light, contact with a particular fluid or a change in pH. While various methods may be used to deploy shaped articles, alternative effective methods are continuously sought.